Long suspected to have contributed to psychoses, fits and
hallucinations in such famous artists and writers as van
Gogh, Poe and Baudelaire, the liqueur absinthe they
cherished contained a potent toxin that Berkeley scientists
now say causes neurons to seriously malfunction.

"Based on what we've discovered, large consumption of old
absinthe would have greatly disrupted the nervous system,"
said scientist John Casida, professor of environmental
chemistry and toxicology. "Our findings could explain many
of the symptoms described in the literature."

Casida said it was not previously known how the
neurotoxin alpha-thujone, found not only in absinthe but
also in many popular herbal medicines, acted on the body to
bring about poisoning or whether the mechanism could account
for strange behaviors noted in many 19th century absinthe
drinkers. Vincent van Gogh, Edgar Allen Poe and Charles
Baudelaire were among them.

The Berkeley researchers discovered that alpha-thujone
acts on the same brain receptor responsible for a form of
epilepsy. The receptor controls the chloride channel that
regulates excitation and keeps neurons under control.

"Basically, alpha-thujone blocks the channel and allows
the neurons to fire too easily," said postdoctoral
researcher Karin Höld, co-author of the study along
with Casida; fellow postdoc Nilantha Sirisoma; and two
collaborators at Northwestern University Medical School,
Tomoko Ikeda and Toshio Narahashi.

"In light of the findings on how alpha-thujone works,
it's not surprising that absinthe had such a remarkable
effect," Casida said.

Symptoms described, for instance, in Wilfred Niels
Arnold's 1992 book on Vincent van Gogh and others who
consumed quantities of the popular 19th- and early
20th-century liqueur included forms of bizarre and psychotic
behavior, hallucinations, sudden delirium, convulsions, and
even suicide and death.

"The question has been sitting around for a century
waiting for someone to say how absinthe and alpha-thujone
might work," Casida said. "We decided to take a look at it
in terms of where the toxin goes in the body and what
happens to it."

Absinthe is made from grain alcohol and the common herb
wormwood. The herb yields a bitter oil used to produce
various formulations of absinthe. This liqueur was very
popular until it was banned broadly in the early 20th
century.

While the historical aspects are interesting, Casida said
he is more concerned about herbal concoctions consumed today
that contain alpha-thujone. Many have not been subjected to
rigorous toxicology tests, he said, including wormwood oil
and cedarleaf oil, which are readily available at herbal
medicinal outlets and contain quantities of the neurotoxin.
Wormwood oil often is used to treat loss of appetite and
stomach, liver and gall bladder disorders. The National
Institutes of Health, which funded Casida's study, have
slated alpha-thujone products for further scientific review
next year.

Absinthe itself isn't the health threat it used to be,
said postdoc Nilantha Sirisoma. Still banned in some
countries but easily available over the Internet, today's
version of the emerald-green alcoholic beverage tends to
have very low alpha-thujone levels, although there is a
great variation among brands and home brew can be
particularly dangerous.

At the moment, "absinthe seems like it's getting more
popular," said Höld, who monitors some of the Internet
traffic on the subject. "It seems to be kind of an 'in'
thing."